Muffler construction



Nov. 23, 1937.- R. J. MMKENZIE ET AL 2,099,858

MUFFLER cous'raucnou Filed Dec. 8, 1934 2 Sheets-Sheet 1 Nov. 23, 1937.

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R. J. M KENZIE ET AL. 2,099,858

MUFFLER CONSTRUCTION Filed Dec. 8, 1934 2 Sheets-Sheet 2 INVENTO/PJT 4kg yz V/d ml r J ATTOR/Vf Y5.

Patented Nov. 23, 1937 PATENT OFFICE MUFFLER CONSTRUCTION Roy J.MacKenzie and Lucien L Haas, Buffalo,

N. Y., assignors to Buflaio Pressed Steel Company, Buffalo, N. Y.

Application December 8, 1934, Serial No. 756,638 14 Claims.(c1.'1a1\-4s) This invention relates to improvements in mufflers orsilencers of the kind which may be used for silencing noises resultingfrom the flow of gases, such, for example, as occur at the exhaust orintake of an internal combustion en-- gine.

It has been found in muiilers of this kind that certain sounds or noisescan best be eliminated by connecting two chambers by means of a soundconducting passage or tuning tube of materially smaller cross sectionalarea than that of the chambers and materially greater length than its.

diameter. In constructionsheretofore used, these tuning tubes weregenerally made of tubing welded to a name connect ng two adjacentchambers, and this construction consequently involved considerableexpense.

The objects of this invention are to provide mufflers with soundconducting passages or tuning tubes of improved and inexpensiveconstruction; also to provide a muiller with passages or tubes madeentirely of sheet metal and secured to the muffler by inexpensive means;also to improve the construction of muiilers by providing r; the samewith sound conducting passages which are formed by two adjacent portionsof the muftier; also to improve the construction of mufflers in otherrespects hereinafter specified.

The improvements herein described may be applied to mutilers of anysuitable or desired construction having more than one sound deadening orsilencing chamber, and the portions of the muiiiers shown in theaccompanying drawings are for purposes only of illustrating theapplication of the sound conducting passages or tubes of this inventionto mufliers, and it is understood that the invention is not limited tothe particular muiiler constructions shown.

In the accompanying drawings:

Fig. 1 is a fragmentary longitudinal central sectional view of a muillerprovided with sound conducting passages embodying this invention.

Figs. 2 and 3 are transverse sectional views thereof respectively onlines 2-4 and 8-4,

Fig. 1.

' Fig. e is a fragmentary longitudinal central sectional view of amuffler showing sound conducting passages of another construction.

Fig. 5 is a fragmentary transverse sectional elevation thereof, on line55, Fig. 4.

Fig. 6 is a fragmentary longitudinal central sectional view of themufiler provided with sound conducting passages of still anotherconstruction. Fig. 7 is a transverse sectional view thereof, on line1-1, Fig. 6.

Fig. 8 is a fragmentary longitudinal central sectional view of stillanother-modified construction.

Fig. 9 is a transverse sectional view thereof, on line 9-8, Fig. 8. i

Fig. 10 is a fragmentary longitudinal central sectional view of amufller showing still another form of sound conducting passage.

Fig. 11 is a transverse sectional view thereof on line "-1 i, Fig. 10.

Referring to Figs. 1 to 3, i5 represents the outer shell and IS theinner shell of a muiller, and ll 9. head at one end of the muffler. Anintermediate shell I8 is arranged between the inner and outer shells andhas its end provided 15 with inwardly pressed or contracted portions 19contacting with the inner shell i6; Other portions of the intermediateshell are bowed outwardly as indicated at 20, to form channels betweenthe inner and intermediate shells through 20 which sound waves or gasimpulses may pass from a chamber 2| formed between the inner andintermediate shells. 22 represents a baiile, which is spaced between theouter and intermediate shells and separates the space between thesetwo25 shells into resonance chambers 24 and 25.

In the embodiment of the invention illustrated in Figs. 1 and 2, soundconducting passages or tuning tubes are provided to connect thechainbers 24 and 28, and for this purpose, the inter- 30 mediate shellis provided with one or more inwardly pressed longitudinally extendinggrooves or channels 26, two of these channels being shown in theconstruction illustrated. A tubular member or sleeve 21 is arrangedaround the por- 5 tion of the intermediate shell which is provided withthe channels or grooves 26. It will be noted that the grooves orchannels are of greater length than the sleeve 21, so that the ends ofthe channels may terminate in openings in the 40 chambers 24 and 25beyond the ends of the sleeve. The sleeve contacts through the greaterportion of its inner surface with the intermediate shell IO and otherportions of this sleeve close the outer or open sides of the channels26, thus 45 forming sound conducting passages or tuning tubes throughwhich sound waves or impulses may travel from one of the connectingchambers to the other. The length of the passages or tubes can,of'course, be easily varied by changing the length of the channels 26and sleeve 21.

In the particular construction illustrated in Figs. 4 and 5, it isdesired to connect two chambers Ill and 3| by means of one or moretuning tubes or sound conducting passages, the cham- 55 bore 8% andilibeing formed between the outer and intermediate shells 3'2 and 33. Inthis case, grooves or channels tit are formed in the intermediate shell33, and the open sides of these grooves or channels are closed by atubular member or sleeve which, in the particular constructionillustrated, is in the form of an annular flange formed integral withthe baffle member 33.

In the construction illustrated in Figs. 6 and 7, two chambers it andill arranged between two shells t2 and lit are connected by means ofsound conducting passages or tuning tubes formed by providing thetransverse bailie member M with an elongated inner flange, forming atubular member or sleeve l5 and which is provided with outwardlyprojecting beads or channels 35, which extend lengthwise of the sleeveand form with the shell d3 sound conducting passages or tubes connectingthe chambers fill and ii.

In Figs. 8 and 9 is shown a construction, quite similar to thatillustrated in Figs. 1 to 3 inclusive, except that in Figs. 8 and 9, thesound conducting passages are formed by providing channels 50 in asleeve iii, instead of in the intermediate shell. The intermediate shell52 closes the inner open faces of the channels, so that soundconducting-passages are formed connecting the chambers and 5d atopposite sides of the baiiie 55.

It will be noted in all of these constructions that to provide thesesound conducting passages or tuning tubes, it is merely necessary tosupply the muiiier with one additional tubular member, namely, a sleevewhich may be either a portion of the transverse baffle or formedseparately therefrom, and this sleeve may cooperate with a shell of themufiler to form with the shell sound conducting passages between the twochambers. The shell and sleeve may be readily fastened together bywelding or in any other convenient manner, and the provision oi separatepieces of tubing and the welding of the same to a baffle are entirelyeliminated, together with the expense which this prior constructioninvolved.

. We claim as our invention:

1. A muiiier including inner, outer and inter mediate shells, a headconnecting the outer and inner shell, said intermediate shellterminating at a distance from said head, a baffle dividing saidintermediate and outer shells into separate sound deadening chambers,said inner shell forming a through passage for gases and sound waves andhaving perforations in portions thereof surrounded by said intermediateshell, said end of said intermediate shell having portions thereofpressed inwardly into contact with said inner shell and otherlongitudinal portions spaced from said inner shell to form a restrictedpassage connecting the space between said inner and intermediate shellswith one of said chambers, and a tuning passage of much greater lengththan width connecting said chambers and terminating at opposite sides ofsaid bafile, a portion of the wall of said passage being formed by oneof the shells connected with said baiile.

2. A muflier having a main passage therethrough for gases and soundwaves, and shells extending about said main passage, and arranged onewithin another, a bafile extending across the space between adjacentshells to form aresonance chamber about said main passage and into whichsound wavesfrom said main passage may pass, and a sleeve snugly fittingone of said shells and contacting therewith throughout a substantialpart of a surface of said sleeve and spaced from said shell at alongitudinal portion thereof to aoeaess form a channel, one end of whichterminates in said resonance chamber and the other end of which receivessound waves from said passage, the length and cross sectional area ofsaid channel being predetermined to cooperate with said resonancechamber to reduce certain sounds in said passage by destructiveinterference, one of said baiiies forming a wall of said resonancechamberand also connecting with said sleeve.-

3. A muffler having a. main passage therethrough for gases and soundwaves, shells extending about said main passage, and arranged onewithinanother, a. bafile extending across the space between adjacentshells to form a resonance chamber about said main passage and intowhich sound waves from said main passage may pass,

. and a sleeve interposed between the inner periphcry of one of saidbafiies and one of said shells and fitting snugly about and contactingwith said shell throughout a substantial part of the inner surface ofsaid sleeve and spaced from said shell at a longitudinal portion thereofto form a channel which terminates at one end in said resonance chamberat one side of said baflle and at its other end at the opposite side ofsaid bafile, the other end of said channel being open to receive soundwaves from said passage, the length and cross sectional area of saidchannel being predetermined with relation to said resonance chamber toform a bottle neck resonance chamber tuned to certain sounds occurringin said passage.

4. A muflier having a main passage therethrough for gases and soundwaves, shells extending about said main passage, and arranged one withinanother, a baffle extending across the space between adjacent shells toform a resonance chamber about said mainpassage and into which soundwaves from said main passage may pass, and a sleeve at the innerperiphery of one of said bafiles and fitting snugly about one of saidshells and cbntacting therewith throughout the greater part of the innersurface of said sleeve, said shell being provided with a longitudinallyextending depression, the opposite ends of which extend beyond the endsof said sleeve to form a channel, one end of which terminates in saidresonance chamber at one side of said bafiie and the other end of whichterminates at the other side of said bafiie in a position to receivesound. waves from said passage, said channel being of a length and crosssection to cooperate with said resonance chamber to form a bottle neckresonator tuned with respect to certain sound waves occurring in saidpassage.

5. A mufiier having a main passage therethrough for gases and soundwaves, shells extending about said main passage, and arranged one withinanother, a ballie extending across the space between adjacent shells toform a resonance chamber about said main passage and into which soundwaves from said main passage may pass, and a sleeve arranged at theinner periphery of one of said baiiies and. snugly fitting about one ofsaid shells and contacting therewith throughout asubstantial part of theinner surface of said sleeve, said sleeve being provided with portionsformed to extend away from the surface of shell to form a channel, oneend of which termi nates at one side of said baflie insaid resonancechamber, and the other end which terminates at the other side of saidbaffie in a position to receive sound Waves from said passage, the crosssectional area and length of said channel being so proportioned withreference to said resonance chamber as to silence certain sounds in saidpassage by destructive interference.

6. A muiiler having a main passage therethrough for gases and soundwaves, shells extending about said main passage, and arranged one withinanother, a baille extending across the space between adjacent shells toform a resonance chamber about said main passage and into which soundwaves from said main passage may pass, and a sleeve telescopicallyarranged within one of said battles and fitting snugly about one of saidshells and contacting therewith throughout a substantial part of theinner surface of said sleeve and spaced from said shell at alongitudinal portion thereof to form a channel which terminates beyondthe ends of said sleeve, one end of said channel terminating in saidresonance chamber at one side of said baffle and the other end of whichterminates at the other side of said baflle in a position to receivesound waves from said passage, said channel forming a neck for saidresonator chamber, and the length and cross sectional area of saidchannel being so formed with relation to said resonance chamber as todeaden certain sound waves in said passage by destructive interference.

7. A mufiier having a main passage therethrough for gases and soundwaves, shells extending about said main passage, and arranged one withinanother, a baflle extending across the space between adjacent shells toform a resonance chamber about said main passage and into which soundwaves from said main passage may pass, one of said bailles beingprovided with an integrally formed tubular extension fitting snuglyabout one of said shells and contacting therewith throughout asubstantial part of the inner surface of said tubular extension andspaced from said shell at longitudinal portions thereof to form achannel, one end of which terminates in said resonance chamber, and theother end of which receives sound waves from said passage; the

length and cross sectional area of said channel being predetermined tocooperate with said resonance chamber to reduce certain sounds in saidpassage by destructive interference, said baffle also forming a wall ofsaid resonance chamber.

8. A muilier having nested inner, intermediate and outer shells, saidinner shell forming a substantially straight uninterrupted passage fromend to end thereof and being apertured in a portion thereof surroundedby said intermediate shell, said intermediate shell terminating at oneend at a distance from the adjacent end of the inner shell and havinglongitudinal portions of its end pressed inwardly into contact with saidinner shell and having another portion between said inwardly pressedportions spaced from said inner shell to form a channel terminating atone end in a space between said intermediate shell and an apertured partof said inner shell and at its other end in a space between said innerand outer shells extending beyond the end of said intermediate shell, asleeve surrounding a portion of said intermediate shell at a distancefrom the end thereof and contacting throughout a substantial portionthereof with an intermediate shell, another portion of said intermediateshell and said sleeve being spaced apart to form a channel terminatingat opposite ends of said sleeve, a transverse annular baflle, the innerperiphery of which terminates at said sleeve, said channel connecting atone end with a resonance chamber, one wall of which is formed by saidballs, and

at its other end in said chamber between said inner and outer shells.

9. In a muiller of the type which silences sound waves by a destructiveinterference, the combination of a pair oi shells arranged one withinthe other, a sleeve arranged in the space between said two shells snuglyfitting one of said shells and having the greater part of one surfacethereof in contact with said shell, and a baiile extending from saidsleeve to the other of said shells,

said sleeve and said first mentioned shell being spaced apart atportions thereof to form between them a'.channel extending from end toend of said sleeve and communicating at one end with said resonancechamber and at the other end with said main passage.

10. In a muifler, the combination of a pair of shells secured one withinanother, a battle forming a connection between said shells and dividingthe space between said shells into separate chambers, means foradmitting sound waves to-one of said chambers, a sleeve having portionsthereof contacting with one of said shells and having other portionsthereof spaced from said shell from end to end of said sleeve andterminating at opposite sides of said baflle to form tuning tubesconnecting said chambers.

11. In a muiller, the combination of a plurality of longitudinallyextending tubular members secured one within another, a transversebaflle forming a connection between two adjacent tubular members anddividing the space between said members into separate chambers, a shorttubular member arranged with a substantial portion thereof in contactwith one of said first mentioned tubular members, at least one of saidtwo last mentioned tubular members being provided with a longitudinalchannel formed therein and of greater length than said short tubularmember to form between said last mentioned tubular members a tuningpassage connecting said chambers, said transverse baille being arrangedwith its inner periphery terminating at said sleeve.

12. In a muiiler, the combination of a pair of shells secured one withinanother, a baiile forming a connection between said shells and dividingthe space between said shells into separate chambers, means foradmitting sound waves to one of said chambers, a sleeve having portionsthereof contacting with one of said shells, said sleeve having a channelformed therein extending from endto end of said sleeve and forming withsaid last mentioned shell a sound conducting passage connecting saidchambers, and means connecting said sleeve with another shell locatedadjacent thereto to force sound waves to pass through said channel.

13. In a mumer, the combination of a pair of shells secured one withinanother, a baiiie forming a connection between said shells and dividingthe space between said shells into separate chambers, means foradmitting sound waves to ing a connection between said shells anddividing E memos the space between said shells into separate chamnestingchambers at opposite sides of said baffle, hers, means for admittingsound} waves to one of and means connecting said sleeve with anothersaid chem'oees, a. sleeve having portions thereof shell located adjacentthereto to force sound contacting with one of said shells and having aWaves to pass through said channel.

5 longitudinal channel formed therein and extencling throughout thelength thereof and forming BUY J. mwmmmwith said shells a soundconducting passage con- LU GEEEI L. HALAS.

